Genetic Improvement of Switchgrass Feedstock for Biofuel Production

Switchgrass (Panicum virgatum), a perennial plant native to the United States, has garnered considerable attention for its potential as a cellulosic biofuel. Only recently has genetic improvement of switchgrass, using novel genetic and genomic tools, been investigated. At Virginia Tech, we initiated a switchgrass molecular breeding program to hasten selection of elite germplasms for biomass production. More than 2,000 switchgrass lines representing 168 core germplasms have been systematically evaluated for their potentials in biofuel production. We identified switchgrass lines condition rust disease resistance, selected a new switchgrass genotype suitable for tissue culture and Agrobacterium-mediated transformation, generated molecular markers for marker-aided selection, and constructed a new switchgrass genetic linkage map for mapping important biofuel traits. We silenced Pv4CL1 in switchgrass by RNAi. The transgenic plant biomass showed a 30% reduction in lignin content and 57% more efficient in fermentable sugar release for biofuel production. We generated transgenic switchgrass lines by overexpression of an Arabidopsis transcription factor, which improved the plant architecture and draught tolerance. An overview of each project will be discussed in the presentation.